What makes someone pack their bags and move to Africa to study bats? Read our interview below to find out more...
What are some of the challenges you face in the field?
Challenges come in many different forms in the field. By working each night over rare desert water, Lina and I risk unexpected wildlife encounters. We limit our capture efforts to the first three hours after sunset to reduce our impacts on thirsty large mammals and target the time of night when bats are typically most active. Rhino, which have notoriously bad eyesight, have approached springs while we are netting and elephants have come to drink during that period as well. When we have enough warning we'll pack up our equipment and move away. Given the skittish behaviour of rhinos, we tend to cancel netting efforts for the remainder of the evening when they are around.
Desert springs come in many shapes and sizes. They also vary in vegetative cover along Namibia’s ephemeral river systems. Almost all wildlife concentrates around this rare, limiting resource. Photograph by Theresa Laverty.
Lastly, we have a few bat detectors stationed more permanently in the field by fly-in tourism camps. Lions carried off one of our bat detectors on the Huab River, shredding the microphone cable. Baboons have been known to gnaw on the same cable at Hoanib Skeleton Coast Camp and crows occasionally fly off with our microphone wind guards!
What types of bats are found in the area and what is the most common bat that can be seen?
We have captured about 600 bats so far from six different families (i.e. groups of species): vesper bats, free-tailed bats, long-fingered bats, horseshoe bats, leaf-nosed bats, and fruit bats. Some species are endemic (i.e. whose entire population occurs only in that region and nowhere else in the world) like the Angolan wing-gland bat (found at Hoanib Camp), the Angolan epauletted fruit bat, and the Namib long-eared bat. The most common bat throughout the region and frequently captured at Hoanib Camp is Roberts's flat-headed bat.
The Angolan wing-gland bat can weigh as little as 3 grams and its entire population is limited to the Namib Desert. Photograph by Flip Stander
Are there any specific threats to bats in the area? – And if so, what can be done to protect them?
Bats in northwestern Namibia most likely face relatively few threats when compared to bats living in more populated and less protected regions worldwide. There are, however, a few notable threats. By changing the distribution of water on the landscape, people may be allowing additional bat species access into an area typically restricted to arid-adapted species. When species that are more reliant on water are also competitively dominant, desert specialist species may be threatened. Likewise, some bat species tend to associate with human settlements and can exclude other native species.
When humans and livestock use water in the region, it is important to monitor water quality to ensure it remains safe to drink. Cattle troughs and water tanks can be designed in ways that are "bat friendly." Since bats drink water while flying, like swifts and swallows, having long fly-ways allows drinking access for less agile flying bats.
Thankfully, most of the region's bats appear to be rock crevice dwellers, so their habitat is not likely to be threatened in the near future. Tree-roosting bats that travel through the area will be reliant on large trees like the ana and camel-thorn trees of the Hoanib River. While old, large trees can escape herbivory, seedlings have been in decline over the years, indicating that perhaps small riparian enclosures should be designed to ensure the continuation of these noteworthy tree species.
How do you carry out your research?
Lina and I work together in the field. We capture bats over water in a mist net, a very fine net about 2 metres high and of varying lengths. The bats are processed quickly. We identify species, age, sex, reproductive status, and take some morphological measurements. For individuals in which we are unsure of species identification, we take a 3 mm wing punch, essentially a hole punch from the wing for genetic sampling, which heals completely within a few weeks. We then record the bat when we release it.
A bat detector, or ultrasonic recorder, runs for the entire three hours to also record the activity of the bats flying in the air that are not necessarily captured in our net. We are often able to identify those bats to species-level based on their call shapes and frequencies.
Theresa Laverty and Lina Mushabati with an African straw-coloured fruit bat. Photograph by Joel Berger
What, in your opinion, is the biggest misconception that people have about bats?
Americans typically use the saying, "You're as blind as a bat," to suggest that someone has bad eyesight. However, bats have incredible night vision. While small, insect-eating bats typically use echolocation (i.e. a behaviour like sonar in which high frequency calls are emitted and bats listen for an echo to locate prey and obstacles), some species heavily rely on eyesight, particularly early in the evening. I always say that if I can still see the mist net from my chair, then it's highly unlikely we'll catch a bat until it gets a bit darker. "Blind as a bat" should really be changed to "blind as a rhino," which really do have bad eyesight.
Other misconceptions include the risks of disease transmission from bats for something like rabies. All mammals can carry rabies and the virus tends to exist in a fraction of a percentage of bat populations. However, bats exhibiting weird behaviours, such as flying during the day for most species, are often the individuals people may come in contact with and could suggest a higher threat of rabies. All cases in which a bat is found in your bedroom should be treated seriously.
Lastly, bats do not aim to fly into human hair, but are likely feeding on insects hovering above our heads in the evening. So next time, thank the bat flying overhead on a hot summer's eve.
Can you share one interesting fact that most people wouldn’t necessarily know about bats…
Bats make up some of the world's smallest mammals and are an extremely diverse order; over 1,300 bat species exist worldwide and one in every five mammal species is a bat.
Some of the vesper bats (i.e the largest and most widespread family of bats) capture insects using their tail membranes and tuck their prey into their mouths by doing a back flip in the air. Of course, this is virtually impossible for people to see at night with their own eyes, but lab studies have been able to video such behaviour.
What has your most memorable adventure been so far during your time in Namibia?
Hard question... During my pilot season, my field assistant Archie Gawusab and I almost stepped on a lion hiding in some sedges while investigating a potential spring site in the Palmwag Concession. Thankfully, the lion ran in the opposite direction from us, but that didn't stop Archie and I from being a bit jumpy that night. A few nights later, we counted down to New Year 2015 from our tents, after wrapping up fieldwork, with a lion and spotted hyaena calling in the distance at midnight.
This year, Lina and I have had some very busy nights, maxing out at 64 bats within two hours at Peter's Pool on the Huab River. Fruit bat captures are always memorable (since they're BIG!), as are nights with elephant and rhino encounters, although those tend to happen at least once each month (i.e. much more frequently than lion sightings).
A rare lion sighting in the sedges around a desert spring. Lions are typically heard, but not seen when working with bats. Photograph by Theresa Laverty
Follow Theresa's updates from the field at: http://voices.nationalgeographic.com/author/tlaverty/